Etching plasma processes

Reece, J., Daniel, D. and Bloom R., Identifying a plasma etch process window. In Understanding Industrial Designed Experiments (Schmidt S. and Launsby R., eds.), 2nd ed. AIR Academy Press, Colorado Springs, CO, 1989. 

Microfabrication involves multiple photolithographic and etch steps, a silicon fusion bond and an anodic bond (see especially [12] for a detailed description, but also [11]). A time-multiplexed inductively coupled plasma etch process was used for making the micro channels. The microstructured plate is covered with a Pyrex wafer by anodic bonding. 

A porous surface structure (100 cm ) in the reaction charmel can be generated by an SFg plasma etch process with sibcon nitride masking [12],... 

GL 16] [R 12] [P 15] By a plasma etch process (see description in ]R 12]), a highly porous surface stmcture can be realized which can be catalyst coated [12]. The resulting surface area of 100 m is not far from the porosity provided by the catalyst particles employed otherwise as a fixed bed. In one study, a reactor with such a waU-porous catalyst was compared with another reactor having the catalyst particles as a fixed bed. The number of channels for both reactors was not equal, which has to be considered in the following comparison. 

The comparison of the resistive property in the plasma etching process between PMMA itself and PMMA sensitized by 2,4,6-tri-tert-butyl phenol is shown in Fig. 12. Following the etching tim the thickness of the PMMA coating becomes thinner. The rate of the decreasing of the film thickness is proportional to the etching time in the former case, but it becomes very slow in the case of the sensitized PMMA. Therefore, the sensitized PMMA is a superior resist than PMMA itself in both properties of the sensitivity and the resistivity. This fact is true in the cases of other sensitizers. 

The past five years have witnessed significant progress in the understanding and control of plasma etch processes. Nevertheless, much of the fundamental chemistry and physics occurring in these reactive atmospheres remains ill-understood, or indeed unknown. The following sections assimilate the information currently available on dry etch processes, and present a framework within which plasma etching can be viewed. 

Jenkins, M.W., Mocella, M.T., Allen, K.D., and Sawin, H.H. (1986), The Modeling of Plasma Etching Processes Using Response Surface Methodology, Solid State Technol, 29, 175-182. 

Bauer S, Wolff I, Werner N, et al. 1992. Toxicological investigations in the semiconductor industry I. Studies on the acute oral toxicity of a complex mixture of waste products from the aluminium plasma etching process. Toxicology and Industrial Health 8 141-156. 

A characteristic of the plasma etching process which is generally observed is that the etch rate of a sample decreases as the area of the sample exposed to the plasma increases This dependence of etch rate on batch size is referred to as the loading effect and an example is shown in Fig. 3.8. The reason for the loading effect is simply that the etching process consumes a significant fraction of the... 

Anisotropic etch on Si can also be achieved by reactive ion etching (RIE), which is a dry (plasma) etch process. In deep RIE, cyclic etch characteristics could be produced on the etched wall [85,86]. 

A flow-pattern map comprises dispersed flow, annular flow, slug-dispersed flow and slug-annular flow [278]. The highest specific interface measured amounts to 16 000 m2/m3. A porous surface structure (100 cm2) in the reaction channel can be generated by a sulfurhexafluoride plasma etch process with silicon nitride masking [278],... 

Studies were also performed with an artificial fixed bed composed of an array of microstructured columns made by a plasma etch process. These columns were made porous to increase the surface area to 100 m2, which is not far from the porosity of catalyst particles in fixed beds, and then coated with a catalyst [278]. The performance of such catalytic microcolumns was compared with that of a catalytic fixed bed reactor. When normalized to the metal content, the reaction rates of the columnar and the particle-containing reactor are similar with 6.5 x 10 5 and 4.5 x 10-5 mol/(minm2), respectively. 

The plasma etching process consists of two components. The first is the physics and chemistry that occur... 

Kushner, MJ. A kinetic study of the plasmaetching process I. A model for the etching of Si and Si02 in CnFm/H2 and CnFm/02. J. Appl. Phys. 1982, 53, 2923-2938 IBID, A kinetic study of the plasma-etching process II. Probe measurements of electron properties in an RF plasma-etching reactor. J. Appl. Phys. 1982, 53, 2939-2946. 

The effects of Ion bombardment were Investigated by Christie t al. (76) on a range of Groups II and IV compounds. They were able to observe stoichiometric changes Induced by the Ion bombardment of surfaces. This has Important consequences for Inert gas ion bombardment and plasma etching processes In the fabrication of semiconductor devices. 

In the development of plasma etching processes, it is important to adjust the process parameters to meet requirements such as high etch rates for silicon, good selectivity over both mask and underlying layer, precise control of the line width, good uniformity, underetching as small as possible, and good control of the wall profiles. 

Process and system non-uniformity (8-3) can affect selectivity requirements. Similarly, the non-uniformity significantly affects anisotropy requirements as well. In general, there are essential trade-offs among anisotropy, selectivity, and uniformity of plasma etching processes, which are discussed, in particular, by Flamm and Herb (1989) and Liebermann and Lichtenberg (1994). 

Basic Plasma Etch Processes Pure Chemical Etching... 

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